ˈlēthēən, lə̇ˈth-, lēˈth- adjective
Usage: usually capitalized
Etymology: Latin Lethaeus of Lethe, Lethean (from Greek lēthaios, from Lēthē Lethe, place of oblivion in the lower world, from lēthē forgetfulness) + English -an; akin to Greek lanthanesthai to forget, lanthanein to escape notice — more at latent
: of, relating to, or causing forgetfulness
the Lethean sensuousness of Keats — Wylie Sypher